| Mar 26, 2026 |
Researchers identify why graphene oxide selectively destroys bacteria while remaining safe for human cells, with applications from toothbrushes to sportswear.
(Nanowerk News) A graphene-coated toothbrush has sold more than 10 million units on the strength of its antibacterial properties, but until now the precise mechanism behind that germ-killing ability was not fully understood. A joint research team at KAIST has now identified how graphene oxide destroys bacteria selectively while leaving human cells completely unharmed, publishing their findings in Advanced Functional Materials (“Biocompatible but Antibacterial Mechanism of Graphene Oxide for Sustainable Antibiotics”).
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Key Findings
- Graphene oxide selectively binds to POPG, a phospholipid present only in bacterial cell membranes, destroying bacterial structures while leaving human cells intact.
- Fibers incorporating graphene oxide retained their antibacterial properties even after repeated washing cycles.
- A graphene-based antibacterial toothbrush developed from the underlying technology has sold more than 10 million units commercially.
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The toothbrush was commercialized through Materials Creation Co., Ltd., a faculty-led startup built on patents from this research. But explaining at the molecular level why the material works so well against bacteria without harming human tissue required a dedicated study. Professor Sang Ouk Kim from the Department of Materials Science and Engineering and Professor Hyun Jung Chung from the Department of Biological Sciences led that effort.
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| Schematic illustration of the selective antibacterial mechanism of GO nanosheets and their chemical structures. (Image: Reproduced from DOI:10.1002/adfm.74695, CC BY) (click on image to enlarge)
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Graphene oxide is a nanomaterial made from an atom-thick carbon sheet bonded with oxygen. It mixes readily with water and can be applied across a range of surfaces and fibers. The team found that oxygen functional groups on the surface of graphene oxide bind selectively to a phospholipid called POPG, a fatty molecule that forms part of bacterial cell membranes but is entirely absent from human cell membranes.
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When graphene oxide encounters a bacterium, it attaches to the POPG in the membrane and disrupts its structural integrity, killing the cell. Human cells, which lack this phospholipid, remain unaffected. The selectivity is chemical rather than mechanical: the material recognizes a molecular target unique to bacteria and ignores everything else.
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Professor Sang Ouk Kim explained, “This study is an example of scientifically uncovering why graphene can selectively kill bacteria while remaining safe for the human body.”
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Beyond oral care products, the researchers demonstrated that textile fibers treated with graphene oxide maintained their antibacterial function through multiple wash cycles. This durability points to applications in apparel, medical textiles, and other products where sustained hygiene performance is essential.
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A related product line called GrapheneTex, which incorporates graphene oxide into textile materials, was used in the uniforms of the Taekwondo demonstration team at the 2024 Paris Olympics. The same textile technology is expected to appear in functional sportswear at upcoming international events, including the 2026 Asian Games.
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Professor Kim emphasized, “By utilizing this principle, we can expand beyond safe clothing without harsh chemicals to an infinite range of applications, including wearable devices and medical textile systems.”
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Sujin Cha, a doctoral student in the Department of Materials Science and Engineering, and Ju Yeon Chung, an integrated MS/PhD student in the Department of Biological Sciences, served as first authors of the paper. Professor Hyun Jung Chung contributed as co-corresponding author. Nanowerk also featured the findings as a Spotlight article titled “Graphene oxide destroys bacteria without harming human tissue.”
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With molecular-level evidence now supporting what commercial sales had already suggested, graphene oxide moves closer to becoming a practical alternative to conventional antibiotics in material applications, from consumer hygiene products to functional sportswear and medical textiles
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